CoreUtils/CGIFormData.cpp

#include "CGIFormData.h"
#include "CGIFormattedData.h"
#include "Exception.h"

namespace coreutils {

   CGIFormData::CGIFormData(StreamReader &reader, ZString contentType, int contentLength, ZString boundary)
     : Parser(reader), contentType(contentType), contentLength(contentLength), boundary(boundary) {
      if (contentType.startsWith("application/x-www-form-urlencoded"))
         mode = URLENCODED;
      else if (contentType.startsWith("multipart/form-data"))
         mode = MULTIPART;
      else
         mode = UNKNOWN;
   }

   CGIFormData::~CGIFormData() {
      delete headerParser;
      delete boundaryParser;
   }

   void CGIFormData::extractPartName(IMFHeader &header) {
      auto &fields = header.getHeaders();
      MString disposition = fields[MString("Content-Disposition")];
      ZString dz(disposition.getData(), disposition.getLength());

      int namePos = dz.find(ZString("name=\""));
      if (namePos != -1) {
         ZString afterName = dz.substring(namePos + 6);
         int nameEnd = afterName.find(ZString("\""));
         if (nameEnd != -1)
            currentName = MString(afterName.substring(0, nameEnd));
      }
   }

   Parser::Status CGIFormData::parse() {
      MString &buffer = reader.getBuffer();

      if (mode == UNKNOWN) {
         state = DONE;
         return Status::COMPLETE;
      }

      switch (state) {

       case INIT:
          if (mode == URLENCODED) {
             state = URLENCODED_BODY;
             return Status::DATA_AVAIL;
          }
          // MULTIPART: the very first boundary line has no leading CRLF
          // (RFC 2046) - handled here directly rather than via IMFBoundary,
          // which always expects the CRLF that terminates a PRECEDING part.
          // Split into two states (find+consume the marker, then separately
          // disambiguate -- vs CRLF) so that if the marker is consumed but
          // there isn't yet enough data to tell -- from CRLF, retrying does
          // not re-search for (and skip past) a marker that is already
          // behind the cursor - the exact bug class already fixed once in
          // IMFBoundary's PREFIX/TAIL split.
          {
             MString marker;
             marker << "--";
             marker << boundary;
             int pos = buffer.find(marker);
             if (pos < 0)
                return Status::INCOMPLETE;
             if (!buffer.ifNext(marker))
                throw coreutils::Exception("CGIFormData: opening boundary vanished between find and ifNext.");
             state = OPENING_TAIL;
             return Status::DATA_AVAIL;
          }

       case OPENING_TAIL:
          if (buffer.getLength() < 2)
             return Status::INCOMPLETE;
          if (buffer.ifNext(ZString("--"))) {
             state = DONE;
             return Status::COMPLETE;
          }
          if (!buffer.ifNext(ZString("\r\n")))
             throw coreutils::Exception("CGIFormData: malformed opening boundary line.");
          state = PART_HEADERS;
          return Status::DATA_AVAIL;

       case URLENCODED_BODY:
          if ((int)buffer.getLength() < contentLength)
             return Status::INCOMPLETE;
          {
             ZString body(buffer.getCursor(), contentLength);
             buffer.setCursor(buffer.getCursor() + contentLength);
             CGIFormattedData parsed(body);
             for (auto &pair : parsed.data)
                storeValue(pair.first, pair.second);
          }
          state = DONE;
          return Status::COMPLETE;

       case PART_HEADERS:
          if (!headerParser)
             headerParser = new IMFHeader(reader);
          if (!checkParse(*headerParser))
             return Status::INCOMPLETE;
          extractPartName(*headerParser);
          delete headerParser;
          headerParser = NULL;
          state = PART_BODY;
          return Status::DATA_AVAIL;

       case PART_BODY: {
          MString marker;
          marker << "\r\n--";
          marker << boundary;
          char *bodyStart = buffer.getCursor();
          int pos = buffer.find(marker);
          if (pos < 0)
             return Status::INCOMPLETE;
          char *bodyEnd = buffer.getCursor();
          // A part whose Content-Disposition includes filename="..."
          // (a real <input type="file">) used to be silently discarded
          // here (currentSkip) rather than stored like any other part -
          // every existing <field type="file"> upload (track audio,
          // presets, project icons) has therefore never actually
          // received real file content via $[fieldname], only ever an
          // empty value. Storing it the same way as any other part is
          // exactly what those call sites already assume.
          if (currentName.getLength() > 0)
             storeValue(currentName, MString(ZString(bodyStart, bodyEnd - bodyStart)));
          currentName = MString();
          state = PART_BOUNDARY;
          return Status::DATA_AVAIL;
       }

       case PART_BOUNDARY:
          if (!boundaryParser)
             boundaryParser = new IMFBoundary(reader, boundary);
          if (!checkParse(*boundaryParser))
             return Status::INCOMPLETE;
          {
             bool last = boundaryParser->isLast();
             delete boundaryParser;
             boundaryParser = NULL;
             if (last) {
                state = DONE;
                return Status::COMPLETE;
             }
             state = PART_HEADERS;
             return Status::DATA_AVAIL;
          }

       case DONE:
          return Status::COMPLETE;

      }
      throw coreutils::Exception("CGIFormData: unreachable state.");
   }

   void CGIFormData::storeValue(MString name, MString value) {
      int index = nameCounts[name]++;
      MString key = name;
      key << ":";
      key << MString(std::to_string(index));
      data[key] = value;
   }

   MString CGIFormData::operator[](ZString name) {
      MString key(name);
      if (key.find(ZString(":")) == -1) {
         key << ":0";
      }
      return data[key];
   }

}